11/29/2018 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Secure Ranging] Date Submitted: [19 September 2005] Source: [Zafer Sahinoglu, Philip Orlik, Andy Molisch] Company [Mitsubishi Electric] Voice:[+1 617 621 7588], E-Mail: [zafer@merl.com] Abstract: [Secure Ranging Proposal] Purpose: [Assist the group to find methods to secure ranging] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Zafer Sahinoglu (MERL)

11/29/2018 Objective To provide security in ranging signaling exchanges such that malicious devices will neither be able to acquire nor jam/manipulate the ranging information Zafer Sahinoglu (MERL)

I want to find where my “thing” is 11/29/2018 Perfect World No malicious devices in the network The originator initiates a TW-TOA signaling, and figures out the range to a target device Perfect World The thing ranging signal OHH, it is 10 meters away I want to find where my “thing” is The thing ranging signal 10 meters Zafer Sahinoglu (MERL)

Real World: Snooper Attack-1 11/29/2018 Real World: Snooper Attack-1 A snooper device observes or listens to the signals in the air in secret to obtain information Real World-I The thing I want to find where my “thing” is ranging signal The thing ranging signal OHH, it is 10 meters away ranging signal 10 meters ranging signal Hmm, I learned this and that The ugly snooper The ugly snooper Zafer Sahinoglu (MERL)

Real World: Impostor Attack-1 11/29/2018 Real World: Impostor Attack-1 An impostor device engages in deception under an assumed name or identity Lesson: make sure whom you are talking to is an authentic device Never talk to strangers Real World-II The thing ranging signal Hmm, there is a thing 26 meters away ranging signal 26 meters The ugly impostor Zafer Sahinoglu (MERL)

Real World: Impostor Attack-2 11/29/2018 Real World: Impostor Attack-2 An impostor device engages in deception under an assumed name or identity Lesson: Don’t believe everything you hear OHH, it is 24 meters away The thing Ranging signal Don’t believe everything you hear Ranging signal I will tell you where your thing is. The ugly impostor Real World-III Zafer Sahinoglu (MERL)

Real World: Jamming Attack 11/29/2018 Real World: Jamming Attack A jamming device interferes with or prevent the clear reception of desired signals Identify existence of a jammer, and back-off for a while With advanced signal processing techniques, remove the interference from the received signal OHH, it is 24 meters away The thing Ranging signal Jamming device Real World-IV Zafer Sahinoglu (MERL)

Let’s get technical now !!! 11/29/2018 Let’s get technical now !!! There are three types of ranging signaling Unsecure fast Secure slow Secure fast Zafer Sahinoglu (MERL)

11/29/2018 Unsecure Fast PHY layers respond to messages without higher layer involvement Timing imperfections and processing times at higher layers avoided, turn around time is minimized (FAST) Ranging preamble is unprotected Target does not know whom it is replying to Zafer Sahinoglu (MERL)

Secure Slow – I (Time Domain, Nanotron) 11/29/2018 Secure Slow – I (Time Domain, Nanotron) Involve MAC layer for authentication Target device dithers the turn-around time Target device reports the dither duration in a separate packet Vulnerable to replay attacks even if the dither is randomized Target is forced to perform ranging on every received packet We should tell him when to do ranging Range Packet Range Packet (ACK) Timestamp packet Ranging notification ACK Range notification packet Zafer Sahinoglu (MERL)

11/29/2018 Secure Fast-II (MERL) Virtually two-step ranging: Notification and Ranging Notification packet carries ranging parameter settings, and can be also used for authentication Ranging packet structure is conventional Complete solution to replay attacks, because for each ranging process settings can be changed Range Packet Range Packet (ACK) Timestamp packet Ranging notification ACK Range notification packet Zafer Sahinoglu (MERL)

11/29/2018 Option-I vs. Option-II Both have the same number of messages in the air Option-II has additional merits Ranging direction can be stated in the notification packet Waveform manipulation provides added level of security in option-II Option-I suffers from replay attacks regardless of whether dither is fixed or derived from a probabilistic distribution A: I want you to know the range between us A: I want to know the range between us Notification packet Notification packet Ranging packet Ranging packet Ranging packet Ranging packet A B A B “B knows the range” “A knows the range” Zafer Sahinoglu (MERL)

Option-I vs. Option-II (cont’d) 11/29/2018 Option-I vs. Option-II (cont’d) Notification packet can be used to do ranging with a sub-set of neighbor nodes (multicast ranging) or all (broadcast ranging) Message efficiency Option-I: N*2 messages Option-II: N+1 messages B B A A 3 2 1 5 C C 1 1 2 3 1 D D 4 6 1 4 S S Option-II allows multicasting like ranging, still using TW-TOA Option-I requires two-way packet exchanges with every ranging neighbor using TW-TOA - Numbers indicate the index of messages in the air - Zafer Sahinoglu (MERL)

Notification Step Ranging Step 11/29/2018 Notification Step Conventional authentication + ranging waveform settings are conveyed to the target in the encrypted payload of the authentication packet Range direction Authentication Packet Structure Ranging Step Ranging symbol (modified) is repeated No need for header or payload Ranging Packet Structure Zafer Sahinoglu (MERL)

Ranging Waveforms for Security 11/29/2018 Ranging Waveforms for Security Ternary-IR Time-hopping-IR Zafer Sahinoglu (MERL)

Ternary-IR Perfect periodic correlation Six length-31 such codes exist 11/29/2018 Ternary-IR Perfect periodic correlation Six length-31 such codes exist Circularly shifting a Ternary sequence moves the periodic autocorrelation function as much as the shift Zafer Sahinoglu (MERL)

11/29/2018 Ternary-IR Illustration of correlator outputs with and without circular shifts (S1 circularly shifted by 5) PRI =15ns , k=5 => The autocorrelation peak shifts by 75ns => 25m deviation Zafer Sahinoglu (MERL)

Security Tool with Ternary-IR 11/29/2018 Security Tool with Ternary-IR The originator and the target decide on both a Ternary sequence and the shift amount to use Conveyed within the notification packet Ranging symbol consists of the repetitions of the shifted symbol waveform Any snooper or impostor may still observe the signal. However, without the knowledge of the shift, they will end up with useless information Zafer Sahinoglu (MERL)

Time-hopping IR Larger family than Ternary-IR (+) 11/29/2018 Time-hopping IR Larger family than Ternary-IR (+) Autocorrelation properties are not as good as Ternary’s (-) Zero correlation zone (ZCZ) around the correlation peak can still be generated by proper code selection If any two TH codes don’t match, the ZCZ gets perturbed Helps against impostors and snoopers who don’t know the exact code Zafer Sahinoglu (MERL)

Time Hopping-IR for Secure Ranging 11/29/2018 Time Hopping-IR for Secure Ranging The originator and the target decide on a TH code within the payload of the authentication packet and use it for ranging It is less likely for a malicious device to track the right TH code TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH1 TH2 Zafer Sahinoglu (MERL)

What is a MUST for Secure Ranging? 11/29/2018 What is a MUST for Secure Ranging? A range notification packet should contain Parameter settings for the next ranging packet exchanges Waveform specification (Ternary or TH) and circular shift (Ternary) Dither of the turn around time ID of the nodes to respond A range packet Header and payload are not necessary. IDs are implicitly represented by the selected ranging waveform Eliminates higher layer involvement Advanced signal processing at the receiver ends to filter out jamming interference Zafer Sahinoglu (MERL)

11/29/2018 Thank You Zafer Sahinoglu (MERL)